DIGITTOINT(3)

💅 DIGITTOINT(3) — ok so bestie, let's talk about turning characters into numbers

okay so real talk, this one lives in the Library Functions Manual, and it's giving "small function, huge glow-up" energy. We're in digittoint and digittoint_l territory and honestly? iconic.

✨ NAME ✨

digittoint, digittoint_l — convert a numeric character to its integer value

🫶 LIBRARY 🫶

Standard C Library (libc, -lc) — she's literally built in, no cap.

🎀 SYNOPSIS 🎀

#include <ctype.h>

int
digittoint(int c);

int
digittoint_l(int c, locale_t loc);

🌸 DESCRIPTION 🌸

So the digittoint() and digittoint_l() functions convert a numeric character to its corresponding integer value. And when I say numeric character I mean she can be any decimal digit or hexadecimal digit — we're inclusive over here. 💖 With hexadecimal characters, the case of the values does not matter, so a and A are both slaying equally. periodt.

The digittoint_l() function takes an explicit locale argument, whereas the digittoint() function use the current global or per-thread locale. iykyk — one of them needs you to tell her which locale to vibe with, the other one just reads the room (the room being whatever global or per-thread locale is active).

ngl if you're out here relying on locale behaviour, double-check which one you're calling. Bestie, read the room. 💀

🔥 RETURN VALUES 🔥

The digittoint() and digittoint_l() functions always return an integer from the range of 0 to 15. Yes, always, no exceptions, she's consistent like that. 🎀

If the given character was not a digit as defined by isxdigit(3) or isxdigit_l(3), the function will return 0. So like… 0 is both a legit answer and the "nope, not a digit" answer. Rip to the ambiguity but we move. 😭

🦋 SEE ALSO 🦋

• ctype(3)
• ctype_l(3)
• isdigit(3)
• isdigit_l(3)
• isxdigit(3)
• isxdigit_l(3)
• xlocale(3)

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and that's the whole page bestie 🫶 this came from Debian, dated December 19, 2022 — shoutout to the source and version, mwah 💅✨